(1) Field of the Invention
This invention relates to water treatment, and more particularly to feeders for introducing treatment chemicals into a recirculating water stream from a swimming pool or the like.
(2) Brief Description of the Art
If untreated, swimming pool water provides an hospitable forum for the growth of bacteria, algae, and other undesirable and potentially unhealthful organisms. It, accordingly, has become common practice to treat pool water on both periodic and continuous bases with treatment chemicals to kill/control such organisms.
Such treatment is typically undertaken via the introduction of chlorine into the pool water at levels effective to kill or control the unwanted organisms. The chlorine source may be in liquid form or may be in a solid form which is then dissolved in the pool water. Among solid sources of chlorine are calcium hypochlorite (cal hypo), dichloroisocyanuric acid (dichlor), and trichloroisocyanuric acid (trichlor).
A variety of feeders exist to deliver chlorine from solid chemical tablets and the like. It is known to utilize a floating erosion dispenser, also known as a xe2x80x9cfloaterxe2x80x9d or xe2x80x9cfeederxe2x80x9d, to provide a continuous release of the chemical. The floater contains the solid chemical and provides a controlled exposure of the chemical to the pool water which in turn controls the speed with which the water erodes the solid chemical to introduce chlorine to the pool water. Exemplary floaters are disclosed in U.S. Pat. No. 4,917,868 and U.S. Design Pat. Nos. 297,857 and 309,493. It is also known to pump pool water through an external feeder which may be incorporated in a circulation system that also provides filtering of the pool water. Among such systems are intermittent spray systems, erosion systems, and partial periodic immersion systems. Examples of such systems are shown in U.S. Pat. Nos. 5,932,093, 5,928,608, 5,441,711, 5,427,748, 5,419,355, 5,384,102, 5,133,381, and 4,208,376, and U.S. Reissue Pat. No. 33,861. As additional background, U.S. Pat. Nos. 5,112,521 and 5,004,549 disclose various solid calcium hypochlorite compositions.
Obtaining proper dissolution of the treatment chemical and avoiding undesirable deposits or residues have posed problems in feeder design. Particular problems exist with the use of commercial calcium hypochlorite pellets which produce calcium carbonate deposits. See e.g., U.S. Pat. No. 6,045,706.
The introduction of treatment chemical to a vortex flow can encourage the dissolution of such chemical via mechanisms which may include the physical agitation provided by the flow and the increased time available for dissolving provided by the flow. The ability to have a relatively continuous flow of water with a more intermittent introduction of chemical may help resist formation of deposits and may provide for a less complex, more economical, feeder construction. Deposits can further be minimized via the introduction of appropriate jets of fresh water at strategic locations where buildup might otherwise occur.
Accordingly, in one aspect the invention is directed to a device for introducing a chemical into a flow of water and having first and second chambers. At least the first nozzle directs water from the flow into the first chamber so as to produce a vortex flow of a body of water in the first chamber. A surface separates the first chamber from the second chamber and defines an outlet for overflow from the first chamber to the second chamber. A second chamber outlet directs water from the second chamber. A reservoir of the chemical has a reservoir outlet positioned to direct the chemical from the reservoir into the body of water in the first chamber. The dissolving of the chemical in the water in the body is encouraged by the vortex flow and the water containing the dissolved chemical is evacuated through the second chamber outlet.
In various implementations of the invention, a second nozzle may direct water from the flow toward a bottom of the first chamber so as to provide a flushing action at the first chamber bottom. A third nozzle bypassing the first chamber may direct additional water from the flow toward the second chamber outlet so as to provide a flushing action at the second chamber outlet. A first float valve may control flow through the first, second and third nozzles and may be positioned to restrict flow when a second chamber water level exceeds a first height. A second float valve may control flow through the second chamber outlet and be positioned to restrict flow when the second chamber water level falls below a second height, lower than the first height. The first, second and third nozzles may be formed as flat fans nozzles. The first and second nozzles may be fed by a common conduit extending along the majority of flow length from the first float valve to the first and second nozzles. The surface may be formed as a reduced height portion of a rim of a wall separating the first chamber from the second chamber. The first nozzle may direct water substantially tangential to an inner surface of the wall. The chemical may consist essentially of calcium hypochloride, dichlorocyanuric acid, trichlorocyanuric acid, or combinations thereof. The water flow may be recirculating flow to/from a swimming pool and the chemical may consist essentially of granular calcium hypochlorite. The first nozzle may have dimensions effective to carry a water flow rate of between 0.2 gpm and 1.0 gpm (0.8 and 3.8 liters/minute), and more preferably between 0.6 gpm and 0.9 gpm (2.3 and 3.40 liters/minute), at 40 psi (0.28 MPa).
The feeder may be incorporated in a pool water treatment system along with at least one pump, a filter, and a conduit network coupling the feeder, pump, and filter to a swimming pool for filtering and chlorinating a recirculating flow of water to/from the pool.
Another aspect of the invention is directed to a device for introducing chlorine from a chlorine-containing pool treatment chemical into a flow of water to/from a swimming pool. An inlet received water from the flow and a nozzle directs received water into a chamber so as to produce a vortex flow of a body of water in the chamber. An opening above the vortex flow receives amounts of the treatment chemical from a reservoir. An outlet returns chlorine-containing water to the flow.
Another aspect of the invention relates to a method for introducing treatment chemical into a body of water at a controlled rate. A feeder is provided having an inlet and an outlet and containing a solid chemical in a chemical reservoir. A flow of water from the body is caused to enter the feeder through the inlet and exit through the outlet to return to the body. A vortex of the water is introduced in a chamber of the feeder. The chemical is dispensed from the reservoir into the vortex. The dispensed chemical is permitted to dissolve in the water in the vortex. The combined flow of water and dissolved chemical is directed from the chamber to the outlet.
In various implementations, the directing may comprise permitting an overflow of water and dissolved chemical from the vortex into a second chamber and passing the overflow to the outlet. Water may be passed from a flow through a conduit bypass in the first chamber so as to provide a flushing action at an outlet of the second chamber, optionally coincident with the feeder outlet. The overflow may represent between 50 and 90% of a total overflow through the feeder. Dispensing may occur at a regular interval. The flow may be continuous and the dispensing may be intermittent. The vortex may be produced by introducing at least a portion of the flow to the chamber with a tangential velocity component of at least 30 fps at a location at least 1 inch from a central axis of the chamber.
The details of one or more embodiments of the invention are set forth in the accompanying drawings and the description below. Other features, objects, and advantages of the invention will be apparent from the description and drawings, and from the claims.